The present invention relates to a modular control apparatus for controlling a technical installation, and in particular but not exclusively to a modular programmable controller for processing a plurality of input signals and generating a plurality of output signals for automatically driving actuators in the technical installation.
A control apparatus in terms of the present invention can be, for example, a modular control apparatus for a configurable or programmable controller. It may be a configurable controller such as, for example, that which is marketed by the applicant of the present invention under the trade name PNOZ® or a programmable controller such as, for example, that which is marketed by the applicant of the present invention under the trade name PSS®, or controllers similar to these. In this case, configurable is understood to mean matching or adjusting a hardware component of the controller, such as, for example, wiring. In this case, programmable is understood to mean matching or adjusting a software component of the controller, for example by means of a programming language.
In particular, applicant's PSSuniversal® provides a modular programmable control apparatus for standard and safety tasks, as is known from the system description “Pilz, PSSuniversal, Programmable Control Systems PSS®, System Description, No. 21256-EN-04”. In this case, a module comprises a first module part in the form of an electronics module part and a second module part in the form of a basic module part, also referred to below as bus module part. The electronics module part is plugged onto the bus module part by virtue of a linear movement.
The electronics module part in this system has two different designs. In a first design, the electronics module part can be an input/output module part (for example for failsafe (FS) or standard (ST) applications). In a second design, the electronics module part can be a voltage supply module part, also referred to as feed module, for feeding a module supply, i.e. an internal supply voltage, or for feeding a periphery supply, i.e. an external supply voltage. It is thus possible for a plurality of separate voltage groups to be formed. For the first design (input/output module part), a corresponding bus module part is used which has bus connections in both directions (towards the right and towards the left) of the longitudinal direction in order to connect the supply voltage from the module adjacent on the left-hand side onto the module adjacent on the right-hand side. This design is therefore also referred to as a design with connected bus. For the second design (voltage supply module part), a corresponding bus module part is required which does not have a connection to the supply voltage bus in a first direction (for example towards the left) and has a connection to the supply voltage bus in the other direction (for example towards the right) in order to pass on the supply voltage only to the modules adjacent on the right-hand side. That is to say that, when forming a new voltage group, the connection on the supply voltage bus needs to be interrupted by a corresponding bus module part. Therefore, this design is also referred to as the design with interrupted bus. Accordingly, two designs of the second module part (bus module part) have to be provided, firstly with connected bus and secondly with interrupted bus.
The external connections are integrated in this system in the bus module part, with the result that the electronics module part, which is arranged on the bus module part, can be replaced without the wiring present at the external connections of the bus module part needing to be replaced, i.e. without rewiring being necessary.
However, it may be desirable that the number of connections is adjustable or variable. A control apparatus in terms of the present invention can therefore be a control apparatus comprising a module with three module parts. One such control apparatus is known, for example, from the X20 system by B&R, as can be seen from the document “X20-System, User's Manual, Version: 2.10 (May 2009), Model number: MAX20-ENG”. In this case, a module comprises a first module part in the form of an electronics module part, a second module part in the form of a bus module part and a third module part in the form of a field terminal module part, also referred to as connection module part. The external connections in this system are accommodated in a separate connection module part.
US 2003/0143896 A1 also discloses three module parts. In each case, one electronics module part can be positioned on a basic module part, and a connection terminal block (connection module part) can be positioned on the front side of the electronics module part. The basic module part has cutouts, which interact with latches, elastic parts or other securing parts of the electronics module part. The securing parts can be moved by two slides in order to secure the electronics module part in a position embedded in the basic module part.
One problem with such control apparatuses consists in that the electronics module part with the connection module part positioned thereon can be removed from the bus module part when the module is still in use, for example when voltages or signals are present at the connections or field terminals of the connection module part. This removal can result, inter alia, in faults on the bus. Furthermore, faults at a connected peripheral (such as an actuator, for example) may arise, in particular when the electronics of the electronics module part are running up or starting up at that time. For example, in the case of a connected or driven actuator, which, as it moves, may pose a risk to people, such a removal of the electronics module part with the connection module part positioned thereon from the bus module part can therefore be safety-critical. Furthermore (in particular in the event of a fault), high voltages can be present at the electronics module part, with the result that the user who is removing the electronics module part with the connection module part positioned thereon from the bus module part can be injured by high voltages.